CHEMICAL APPARATUS. 



89 



Air Balloons. (Fig. 541.) The air- 

 halloon consists of a light bag, formed of 

 goldbeater's skin, of a globular or elliptic 

 shape, and rendered air-tight by a coat- 

 ing of varnish. When thus prepared, it 

 must be distended with some elastic fluid, 

 lighter than common air, as hydrogen, 

 and it will thence acquire an ascending 

 power, equal to the difference between 

 its weight, including the attached car and 

 its contents, and that of the bulk of atmo- 

 spheric air which it displaces. 



Price, 12 in. long, 56 cts. ; 15-in. 75cts. 

 " 18 in. $1.25; 27 in. $1.75; 

 " 32 in. $2.50; 36 in. $3.25. 



Fig. 542. 



Fig. 541. 



Fig.5t3. 



Ether Jet. (Fig. 542, as above.) This is an oblong 

 spherical bulb with a long carved jet on one end, and a 

 handle to hold by at the other; it is filled by warming the 

 ball, and then immersing the jet in ether ; on cooling, the 

 ether will fill the ball. If it now be suffered to boil by the 

 heat of a lamp, the ether may be set on fire as it is forced 

 out of the vessel by the pressure of its vapor. It burns in 

 a beautiful arch of great brilliancy ; if alcohol be substi- 

 tuted for ether, the light is less brilliant, showing that 

 different vapors and gases evolve different quantities of light 

 when ignited. Price, in glass, $0.38. 



" in metal, $1.00. 



Deflagrating Jar and Spoon. (Fig. 543, as above.) 



The first is a glass jar, with a large opening at the top for 



the insertion of a cork or stopper, through which is thrust 



in some experiments a metal spoon, shaped as in the cut 



8* 



